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A Broken Clock Is Right Twice a Day: [Ce/Mg] Is Not a Universal Chemical Clock
Liam O. Dubay, Jennifer A. Johnson, James W. Johnson +14
The ratio of -process to -element enrichment () has been proposed as a ``chemical clock,'' or a means to estimate stellar ages. However, the age-- relation vari…
Spectroscopic Follow-up of Young High- Dwarf Star Candidates: Still Likely Genuinely Young
Yuxi Lu, Catherine Manea, Maryum Sayeed +9
The question of whether genuinely young high- stars exist has been discussed for over a decade since their discovery from asteroseismology of giant stars as it is challenging to…
The Milky Way Radial Metallicity Gradient as an Equilibrium Phenomenon: Why Old Stars are Metal-Rich
James W. Johnson, David H. Weinberg, Guillermo A. Blanc +12
Metallicities of both gas and stars decline toward large radii in spiral galaxies, a trend known as the radial metallicity gradient. We quantify the evolution of the metallicity gr…
The APO-K2 Catalog. II. Accurate Stellar Ages for Red Giant Branch Stars across the Milky Way
Jack T. Warfield, Joel C. Zinn, Jessica Schonhut-Stasik +11
We present stellar age determinations for 4661 red giant branch stars in the APO-K2 catalog, derived using mass estimates from K2 asteroseismology from the K2 Galactic Archaeology…
Galactic Chemical Evolution Models Favor an Extended Type Ia Supernova Delay-Time Distribution
Liam O. Dubay, Jennifer A. Johnson, James W. Johnson
Type Ia supernovae (SNe Ia) produce most of the Fe-peak elements in the Universe and therefore are a crucial ingredient in galactic chemical evolution models. SNe Ia do not explode…